Perforator



' if 29 942 K. cALvER-r 2,299,210 PERFoRTon Filed April 14, 1941 2 Sheets-Sheet 1 u ggg Jam dwf/ @www M@ v%g Get. 20, 1942. K CALVERT 2,299,210

PERFORATOR Filed April 14, 1941 2 Sheets-Sheet 2 Patented ocr. 2o, 1942 UNITED STATE S PATENT OFFICE PERFORATOR Kuhn Calvert, Chauk, Burma, India Application April 14, 1941, Serial No. 388,4l2

Claims.

where oil bearing sands forming productive horii zons have been passed up in the drilling of the well. The present invention has for a primary object to improve the bullet type casing perforator of my Patent 2,200,487, granted May 14,

1940, to facilitate the firing and reloading of thef fuse chamber containing an electric detonator.

A further object of the invention is to provide an improved detonator for casing perforators of the type disclosed consisting of a relatively small self-contained 4unit that may be easily inserted and removed from the casing and also readily connected with the necessary electric wires for ring the same.

A further object of the invention is to provide a bullet type casing perforator having a plurality of powder chambers with gun units associated with each powder chamber and which chambers are arranged in groups of four so that the groups may be iired individually, in pairs or simultaneously.

A further object of the invention is to pro- I,vide a casing perforator having powder cham- ?hers with a gun unit associated with each cham- "er and additionally having an improved electric `detonator for each group of four chambers so hlt they can be fired individually, in pairs or iriultaneously at the will of the operator.

With these and other objects in view the invention masi, consist of certain novel features of constructio' and operation, as will be more fully described and particularly pointed out in the specication, drawings and claims appended hereto.

In the drawings which illustrate a`n embodiment of the invention and wherein like reference characters designate like parts- Figure l is an elevational view of a bullet type casing perforator coming within the invention and embodying an improved electric detonator;

Figure 2 is an elevational view of the upper intermediate section of the perforator showing association with their respective powder chamber;

Figure 3 is an elevational view of the lower section of the perforator also showing the gun units, the detonator units and their spiral orientation;

Figure 4 is a vertical sectional view of the head end section of the periorator showing the cable attaching means and the electric detonating mechanism;

Figure 5 is a fragmentary sectional view showing a detonator unit and illustrating the improved electric detonator of the invention;

Figure 6 is a fragmentary sectional view illustrating the structure for electrically connecting adjacent sections and which structure includes the improved electric detonator;

Figure 7 is a view illustrating the electrical connections for the several detonator units in diagrammatic form;

Figure 8 is a transverse sectional view taken along line 8 8 of Figure 3 showing a powder chamber. gun unit and removable loading plug for the powder chamber;

Figure 9 is a sectional view taken along line 9-9 of Figure 2 illustrating the location and arrangement of the several vertical bores extending through the sections; and

Figure 10 is a detail sectional view illustrating the construction of the improved electrical detonator.

As shown in Figure 1 of the drawings, the perforating unit of the invention consists of a head piece I0, an upper intermediate section II, and a lower section I2 having a rounded nose portion I3, all of said parts being formed of metal such as steel or a steel alloy. In Figure 4 thehead piece is shown as consisting of two parts I`4 and I5 having threaded connection at I6, which enables the lower part to receive packing I'I and a gland nut I8 in surrounding relation with the cable 20 which extends longitudinally through the head piece. Part I4 is provided with fiat portions 2l in opposed relation for receiving a wrench which facilitates assembly of the head rliilece with respect to the intermediate section In my Patent 2,200,487, granted May 14, 1940,

it was necessari7 to unscrew the head piece in order to renew the fuse each time the gun was used. This is not necessary with the improvements of this invention which essentially consist in the provision of removable detonator units in the intermediate section and lower section of the spiral orientation of the gun units and their the gun, each detonating unit providing a thermal element for firing the gurlI limits associated therewith. The head piece l is-.threadedly connected to the intermediate section by the threads 22 and said section. provides the pin 23 for connection with cable 20. Two wires forming conductors extend from the cable in advance of its connection with pin 23. Wire 24 is electrically connected with the detonator units in lthe intermediate section, whereas wire 25 byn plug and projects a distance from the respective sides thereof. Insulating plugl 29 is located within. a recess provided therefor which is normally closed by the detonator cap 3| having threaded connection with the intermediate section and therefore being removable from said section. The bottom of cap 3| is recessed to accommodate the contact screw 32 threaded to one end of member 30. 'I'he other end of member 30 receives a pair of nuts 33 which electrically connect the conductor wire 34 to the member. Member 36, contact 28 and wire 24 comprise the elements for supplying lan electric current to the detonator unit located in the upper end of sec-` tion Il and protected by cap 3|. When cap 3| is removed the insulating disc 35 can be removed and also the insulatingwasher 36. The operator is then able to insert the detonator 31 in the rev cess provided therefor and electrically connect the same by means of wire 38' with contact screw 32. Since one end of the detonator J1 is grounded to the metal of section it is only necessary to supply current to wire 24 electrically connecting with member 30 and thus with wire 38.

The detonator unit above described is prol vided for firing a group of gun units. In the illustrated embodiment four gun units are located in intermediate section Il immediately below the detonator unit sealed within its recess by cap 3|. Another detonator unit sealed by cap 4| is also provided in the intermediate section i! and below the same are four gun units. The gun units are identical in construction and operai tion to those shown in my Patent 2,200,487. Each unit includes a recess providing at its inner end a powder chamber 42 and having a threaded portion 43 for receiving the gun barrel 44 horizontally positioned in the section and which is oriented so that the four gun units of each group are ninety degrees apart. The barrel 44 has a bore 45 for receiving a bullet 46 and rubber plug 41 which is placed in the bore following the positioning of the bullet therein in order to prevent water, oil or other liquid from coming into contact with and spoiling the explosive powder within chamber 42. Each powder chamber is filled by means of an auxiliary opening 48 leading into the side of the powder chamber and normally closed by the threaded plug 50. It will be noted that each barrel extends well within its respective powder chamber, in fact, each barrel extends almost to the rear wall of lits powder chamber. This is desirable since it increases the length of the bore and accordingly the bullet will issue with greater force and can be more accurately directed. After the bullets are in place the threaded plug 56 is removed and each powder chamber is lled with an explosive charge. By filling the chambers through this auxiliary opening a relatively safe procedure is provided since the gn units can be inserted when the chambers are empty. It is therefore not necessary to screw the gun units down onto a charge of explosive powder.

The powder chambers 42 of each group of gun units are connected by a longitudinally extending firing bore. For the detonator 31 a ring bore 40 is provided which is in communication with the detonator and has connection by a continuation of firing bore 48 with the four powder chambers located in the upper section Il immediately below this detonator unit. It will be understood that when detonator 31 is electrically red that the four gun units associated therewith will also be fired. This comes about by reason of the fact that when the powder chambers are filled with powder some of the powder will of course find its way into and illl the firing bore 40. Detonator 31, as best shown in Figure l0, is likewise filled with powder which when ignited by fusing the thermal element 5| will in turn ignite the powder in the rst of the powder chambers adjacent thereto by the longitudinal firing bore 40 and accordingly the other powder chambers having connection therewith by the continuation of the bore 40 will be fired in succession. 'I'his can best be understod by referring to Figure 2.

Referring more particularly to Figure l0, each detonator includes a cylindrical shell 52 of insulating material having ametal contact 53 and a metal jacket 54 protecting its rear end. The thermal element 5| extends from metal contact 52 to the metal jacket 54 and the jacket is provided in order to ground the electrical circuit at this point.

As previously explained, the second group of powder chambers is red by a separate and distinct detonator located within the recess sealed by the cap 4|, Figure 5. Conductor 34 electrically connects member 36 with a similar member 55. A small bore 56 extends longitudinally of intermediate section to provide a passage for insulated conductor 34 so as to electrically connect the upper detonator unit with the lower detonator unit. Member 55 is encased in an insulating plug 56 suitably held within its recess by threaded screw 59. The contact screw 58 electrically connects the wire 60 to member 55 and said wire 60 in turn leads to the detonator 51. Said detonator 51 is similar to 31, having a metaljacket for grounding the electrical circuit to the intermediate section at this point and includmg a thermal element 5| embeddedA in an explosive charge of gun powder. The longitutindal firing bore 62 extends downwardly from the detonator and connects the explosive charge of the same with the four powder chambers located in this section below the detonator unit. With the cap 4| in place the insulating disc 35 of this unit is securely held so as I retain the insulating washer 36 also within time chamber receiving the detonator. Said washer in effect seals the chamber as only one small opening is l provided for the wire 60 whereby the unit is connected to the electrical circuit. When the elec- -trical circuit including member 55 and wire 34 is closed the thermal element fuses to ignite the powder within the unit 51 and in a manner as As best shown in Figure 6, said bore has an angular direction at the lower end of said intermediate section in order that conductor 25 ex` tending therethrough may electrically connect with the center contact 64. Contact 64 is located within the inverted cup 65 formed of insulating material and positioned in the lower end of the intermediate section II which end is threaded at 65 so that the same may be connected with lower section I2. 'Ihe electrical circuit from wire 25 to contact 54 is continued by the fixed contact 61 provided by the lower section I2 and which is likewise insulated from said section by part `88. Contact 51 extends downwardly for some distance so as to have connection with the member of the upper detonator unit provided by said lower section and which unit is sealed within its recess by cap 1 I. The construction of this detonator unit is substantially the same as that shown in Figure 4. Member 1I) is insulated by plug 59 and at one end includes a contact screw 12 and at its other' end is provided with nuts 13 for conductor 14. The wire 15 from contact screwY 12 electrically connects with the thermal element of the detonator 11 and which is similar to that shown in Figure 10. The longitudinal firing bore 18 extends from detonator" in a downward direction substantially centrally of the lower section I2 to connect with the four powder chambers located below the detonator. When the explosive charge within detonator 11 is electrically ignited by thermal element 5I the fire is continued by the firing bore and is conducted bythe same to the respective powder chambers so that their respective gun units are red in succession.

The second detonator unit in the lower section I2 is electrically connected to insulated conductor 14 which extends through passage 18 provided therefor. The details of this second detonator unit are not shown except in the elevational view,

Figure 3, but it will beunderstood that the individual elements making up said detonator unit are in all respects similar to that shown in Figure 5. In other words, the second detonator for the intermediate section II is repeated for the unit corresponding thereto in the lower section I2. Each section is very similar in construction and in operation.` Four gun units are provided for each group and each gun unit includes a powder chamber 42 and barrel 44 as shown in Figure 8. The powder chambers of each group are connected by a longitudinal firing bore and each firing bore at its upper end is in communication with a detonator such as shown in Figure 10. 'Ihe detonator is connected by the conductors and wires described to a source of electricity, as will also be understood by reference to the wiring diagram shown in Figure '1. The main element of each detonator unit in addition to the detonator thereof includes a horizontally positioned metal member 30, 55 and 10 which in each instance is encased in an insulating plug so that the member is insulated from the metal of its particular section. The structure for connecting member 10 with the conductor wire 25 includes several additional elements which are not found in Figure 4 since the elements are not necessary to connect the member 30 with the conductor wire 24. The additional structure shown in Figure 6 makes it possible to mechanically connect, the intermediate section Il with the lower section I2 as by the threads 65 and to automatically complete the electrical circuit required for the detonator units in said lower section.

Referring to the wiring diagram of Figure 7, the conductor wires 24 andl 25 join at 80 to the main conductor wire 8l having switch 82. The switch is closed by the operator after the casing Y perforator has been lowered to the desired depth within an oil well. VThe closing of the switch 82 closes the electric circuit including the source of current, namely, the battery 83, and the detonators 31, 51 and 11. One terminal of the battery is grounded and the detonators are each grounded so that the metal of the perforator is used as a return conductor. If the'thermal element in each detonator is of the same electrical resistance the said elements will be fused simultaneously and the gun units of each group will be ilred at approximately the same time. It is possible, however, in accordance with the invention, to re the gun units of the various groups at different times either in pairs or individually. This can be accomplished by changing the electrical resistance of the thermal element in the various detonators. The potential or voltage of the battery 83 can be progressively increased so that the thermal elements are fused according to their resistance. For example, the thermal element in 31 may have the lowest resistance, with the thermal element in 51 having a higher resistance. The first charge of electricity upon closing switch 62 would have a'voltage suflicient to fuse only the thermal element in 31. As the voltage of the current is increased eventually the element in 51 is caused to fuse and fire its respective gun units. In a similar manner the detonators in the lower section -I2 can be adjusted to re simultaneously with those in the intermediate section II or at different times.

After the gun has been fired the detonator caps must be removed so that access may be had to the detonator units for placing new detonators therein. This is a relatively simple procedure and may be done either before or after the powder chambers 42 have been filled with their explosive charges. Also the units can be inserted Without separating the sections of the member from each other. A further improvement of the invention resides in the provision of electrical contact means between sections II and I2 which permits mechanical removal of one section from the other and their connection again without interfering with the wires and contacts of the electrical circuit. The central contact 64 is yieldingly forced in a downward direction by a spring" y a plurality of sections forming an elongated member, a plurality of gun units provided by the member each having association with a powder chamber, a longitudinal firing bore connecting ing a plurality of sections forming an elongated member, a plurality of detonator units located in spaced relation longitudinally of the member, gun units located below each detonator unit to including a gun barrel positioned within avrecess which terminates in a powder chamber for containing an explosive charge, each detonator unit including a contact member Aelectrically connecting with a source of current supply and a detonator having electrical connection with the contact member, and a longitudinal firing bore for each group of gun units intersecting the powder chambers of its group and having communication with the detonator of its respective detonator unit.

3. In a gun type casing perforator compris ing a plurality of sections forming an elongated member, a plurality of detonator units located in spaced relation longitudinally of the member, spirally arranged gun unitsV located below each detonator unit to form a group with respect thereto, each gun unit including a gunbarrel n form a group with respect thereto, each gun unit groups, and a longitudinal iiring bore extending from each detonator unit and intersecting the explosive charges of its respective group of gun units for firing the gun units of each group successively.

6. In a well perforating gun, in combination, an elongated -body member having a plurality of vertically spaced gun openings and at least one detonator opening, said openings each extending inwardly from the outer surface of the member, a barrel to receive a projectile located within each gun opening and said barrel forming a powder chamber with the inner wall of its gun opening, a substantially vertical firing bore oi relatively small diameter connecting the said powder l chambers with each other and extending to and connecting with the detonatorl opening, and a detonator unit located within the Vdetonator opening.

7. In a well perforating gun, in combination, Y

. to and connecting with the de tonatorlopening,

a .detonator unit located within the detonator opening and including a thermal element having an explosive charge surrounding the same, said element and explosive charge having a location within said opening to directly communicate with' said tiring bore.

positioned within a recess which terminates in a powder chamber for containing an explosive charge, the detonator units each including an insulated contact member electrically connected with a source of current, a detonator electrically l connected to the contact member, anda removL- able cap for retaining the detonatorwithin its recess, and a longitudinally extending firing bore for each group of gun units intersecting the powder chambers of its group and having com-.-

munication with the detonator of its respective detonator unit. i

4. In a well casing perforator, an elongated member having a plurality of detonator units member, a plurality of gun units located below each detonator unit to form a group with respect theretoy a longitudinally extending firing bore f member including a head end portion, a lower' en d section and at least one intermediate section, a cable attached to the head end portionv for suspending the member and whereby the same may be lowered into a well casing, a plurality of explosive charges carried by the intermediate section and said lower end section, a gun unit associated with each explosive charge, at least two detonator units provided by each section and positioned so as to divide the gun units into located. in spaced relation longitudinally of the 8. Inv a well perforatng gun, in combination,

an elongated body member having aplurality of' vertically spaced gun openings and at least one detonator opening,vsaid openings cach extending inwardly from the outersurface of the member, a barrel to receive a projectile located within each gun opening and said barrel forming a powder chamber with the inner wall of its gun opening,

a substantially vertical ring bore of relatively small diameter connecting the said powder chambers with each other and extending to and connecting with the detonator opening, a detonator unit located within the detonator opening, and conductor means extending from the member at one end thereof and electrically connecting with the said detonator unit.

9. In a well perforating gun, in combination, an elongated body member having a plurality of vertically spaced gun openings and at least two detonator openings, said openings each extending inwardly from the outer surface of the member and the detonator openings being located vertically to dividethe gun openings into groups, a barrel to=receive a projectile located within each gun opening and saidbarrel forming a powder chamber with the inner wall of its gun opening, an axially disposed firing bore connecting the powder chambers of each group and extending to and communicating with the detonator opening for its respective group, a detonator unit located within each said detonator opening, and conductor means extending through a vertical passage in the member for electrically connecting the detonator units.

10. In a well perforating gun, in combination, an elongated body member having a plurality of vertically spaced gun units extending from the outer surface inwardly of the member and each communicating at its inner end with a powder chamber, said member having a detonator opening in associated relation with the gun units, an axially disposed firing bore connecting the said powder chambers with each other and extending into and communicating with the detonator opening, an insulated contact member located Within the detonator opening and electrically connecting with a source of current, a detonator located Within said opening and removably positioned in communication with the ring bore, means electrically connecting the detonator with the contact member, and a removable cap for closing said opening to seal the detonator Within the same.

KUHN CALVERT. 

